Well tool apparatus

ABSTRACT

Apparatus for selective engagement with and disengagement from a well tool comprising: a tubular body having radial windows therein; a plurality of latches carried by the body for radial movement in the windows between retracted positions, engaging the well tool, and extended positions, disengaging the well tool; a cam member carried by the body and axially movable relative thereto to effect movement of the latches between the retracted and extended positions; and cooperable retainers carried by the body and the cam member permitting axial movement of the cam member in response to a predetermined axial force applied thereto. The latches may comprise pivot portions and longitudinally disposed finger portions extending therefrom so as to render the latches pivotable about the pivot portion, permitting radial movement of the tips of the finger portions between the retracted and extended positions. The cooperable retainers may comprise a plurality of collet fingers, on the cam member, having threaded tips engageable with corresponding threads carried on the body.

United States Patent [191 Dinning Feb. 4, 1975 WELL TOOL APPARATUS [75] Inventor: Robert W. Dinning, Houston, Tex.

[73] Assignee: Macco Oil Tool Company, Inc., Houston, Tex.

22 Filed: June 27, 1973 21 Appl. No.: 373,956

[52] US. Cl 294/863, 294/8618, 294/862 [51 1 Int. Cl. E2lb 31/02 [58] Field of Search 294/86.1, 86.17,

Primary Examiner-Richard A. Schacher Assistant Examiner-Johnny D. Cherry Attorney, Agent, or Firm-Torres & Berryhill [57] ABSTRACT Apparatus for selective engagement with and disengagement from a well tool comprising: a tubular body having radial windows therein; a plurality of latches carried by the body for radial movement in the windows between retracted positions, engaging the well tool, and extended positions, disengaging the well tool; a cam member carried by the body and axially movable relative thereto to effect movement of the latches between the retracted and extended positions; and cooperable retainers carried by the body and the cam member permitting axial movement of the cam member in response to a predetermined axial force applied thereto. The latches may comprise pivot portions and longitudinally disposed finger portions extending therefrom so as to render the latches pivotable about the pivot portion, permitting radial movement of the tips of the finger portions between the retracted and extended positions. The cooperable retainers may comprise a plurality of collet fingers, on the cam member, having threaded tips engageable with corresponding threads carried on the body.

15 Claims, 6 Drawing Figures PATENTEU FEB 41975 sum 30F 3 WELL TOOL APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pertains to well tools. In particular it concerns apparatus for running and/or pulling well tools in a well conduit.

2. Description of the Prior Art There are many types of well tools which are installed in a well conduit after the conduit has been run in a well hole. For example, subsurface safety valves are frequently installed in the tubing string of a well. A gas lift valve may be installed in the tubing string. In fact, several gas lift valves may be installed at various levels within the tubing string to allow injection of gas into the flowing string of the well to artificially lift production fluids therethrough. Many other types ofwell tools may be installed or removed from a well conduit.

In the past, valves or other devices which were installed in or removed from a well conduit were done so with wireline type equipment. With such equipment, a running or pulling tool is provided for attachment to the device to be run into the well conduit. The running or pulling tool is in turn connected to a wireline which runs to the surface of the well so that the device may be lowered into the well or pulled out ofthe well by the wireline. The running tools are usually provided with some type of releasable latch so that, once the device is in place, the running tool and wireline may be removed from the conduit. In the case of pulling tools, a self engageable latch is provided for latching on to the device to be pulled.

In recent years, a new line of equipment has been developed for running and pulling down-hole devices in wells. This line of equipment has arisen out of the need for better methods of servicing offshore wells, deviated wells, extremely deep wells, and wells with other characteristics which render wireline type methods difficult or impossible to use. This recently developed equipment is sometimes referred to as pumpdown or through-flow-line equipment. Examples of such equipment, as applied to running and pulling gas lift valves, may be seen in U.S. Pat. Nos. 3,334,690 Garrett and 3,419,075 Brown.

A typical pumpdown or through-flow-line assembly may include the device to be run into the well, e.g. a gas lift valve, and a latch assembly for locking the device in place. It will also normally include a running tool for attachment to the device to be installed in the well. Attached to the running tool is a motor assembly by which the pumpdown equipment is propelled through the well conduit. The motor assembly usually consists of two or more seal assemblies provided with external resilient sealing members, having flexible lips, which provide differential pressures by which the entire assembly or train" may be pumped into or out of the well. Various other types of equipment, such as jars, accelerators, or the like, may be included in the pumpdown assembly or train. Since the train may have to travel through flowline loops or other curving paths, the various components ofthe train are usually connected by some type of flexible joint.

Various types of running or pulling tools may be used with pumpdown type equipment. Even some of the tools originally designed for use with wireline equipment, may be suitable. However, most of the running and pulling tools of the prior art, are not suitable for pumpdown equipment for one reason or another. For example, the running or pulling tool may be too long, increasing the radius through which the pumpdown assembly may be propelled. Thus, new types of running and pulling tools must be used. Furthermore, running and pulling usually requires a slightly different type of tool. In fact, two separate tools are usually required for running and pulling.

SUMMARY OF THE INVENTION The running and pulling tool ofthe present invention comprises: a tubular body member having radial windows therein; a plurality of latches carried by the body member for radial movement in the windows between retracted positions, engaging the well device, and extended positions,,.disengaging the well device; a cam member carriedby the body member and axially movable relative thereto to effect movement of the latches between the retracted and extended positions; and cooperable retainer means carried by the body member and the cam member permitting axial force applied thereto. The latches may comprise pivot means and longitudinally disposed finger means extending therefrom, the latches being pivotable about the pivot means between the retracted and extended positions. The cooperable retainer means is operable upon removal of the predetermined force to retain the cam member in an axially displaced position, retaining the latches in their extended positions. The retainer-means may comprise retractable and expandable collets having threads thereon engageable with a corresponding helical threads on the body member and being alternately retracted and expanded in response to the predetermined axial force to permit the axial displacement of the cam member relative to the body member.

This unique combination running and pulling tool, is primarily designed for use with pumpdown assemblies or trains. The tool connects the device which is to be installed in the well, e.g., gas lift valve, to the motor assembly and other commponents of the pumpdown train. Then the train is pumped into the well until the device is properly latched in place. A predetermined pressure level then causes latches of the tool to release the device and allow removal of the motor assembly and remaining portions of the pumpdown train. The same tool may be used for retrieving the device and may, by the installation of a single shear pin, be adapted for emergency release when such becomes necessary.

Thus, the apparatus of the present invention may be used both for running and pulling devices, such as gas lift valves, in a well conduit. It's design permits an extremely short length, allowing passage of the pumpdown assembly, with which it is used, through very short radius turns. The unique design of the tool permits it to be used both for running and pulling without major modifications. Furthermore, it is simple to operate and economic to manufacture. Many other objects and advantages of the invention will become apparent from a reading of the description which follows in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are quarter-sectional elevation views of a pumpdown assembly, utilizing a running and pulling tool according to a preferred embodiment of the invention, FIG. IA illustrating the upper part ofthe assembly and FIG. 18 being a continuation thereof and illustrating the lower part of the assembly;

FIG. 2 is a detailed quarter-sectional elevation view ofthe running and pulling tool of the present invention, showing the tool in its normal running position in engagement with a portion of the device which is to be installed in a well;

FIG. 3 is a detailed quarter-sectional elevation view of the running and pulling tool, illustrating the tool after application of a predetermined force to release it from the well device, allowing removal of the tool and the remainder of the pumpdown assembly from the well;

FIG. 4 is a detailed quarter-sectional elevation view of the running and pulling tool of the present invention, illustrating the tool, as it is used in pulling, in initial engagement with the pulling neck of the well device to be removed from the well; and

FIG. is a detailed quarter-sectional elevation view ofthe running and pulling tool of the present invention, illustrating its operation under emergency conditions in which a shear pin is utilized to release the running and pulling tool for removal from the well.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring first to FIGS. 1A and 13, there is shown a pumpdown assembly or train which comprises, from the bottom up, a latch assembly L, packing assembly P gas lift valve assembly V, packing assembly P running and pulling adaptor A, running and pulling tool T, motor units M M M M and emergency pulling neck N. The entire assembly is assembled as a unit and may be pumped downwardly through a tubing string (not shown) for installing the gas lift valve assembly V, along with related components latch assembly L and packing assemblies P P within a receiver (not shown) which is connected in the tubing string.

The latch assembly L is provided with outwardly biased radial latches l, which automatically engage corresponding recesses in the receiver. The profile of the latches 1 and the corresponding latch recesses within the receiver are so designed that the latches 1 will not engage any recesses which might lie between the receiver and the surface of the well. Such a latch assembly is shown and described in detail in US. application Ser. No. 344,568, now US. Pat. No. 3,827,491 and will not be further elaborated on herein except to say that the latch assembly L engages the corresponding latch recesses in the receiver locating the gas lift valve assembly V at the proper location.

The gas lift valve assembly V includes a tubular mandrel 2 in which a gas lift valve 3 is installed. The gas lift valve 3 may be of any conventional design and is used to control flow of fluids between the tubing string and a surrounding casing string (not shown). For this purpose, the receiver is provided with a port (not shown) in registration with a corresponding port 5 in the valve mandrel 2. The gas lift valve 3 then controls the passage of fluids between the tubing string and the surrounding casing string by controlling flow through the ports, including 5. The gas lift valve 3 may be one designed for either tubing or casing injection. Af for as the present invention is concerned, it makes no difference.

In order for a gas lift valve to be effective, it must be properly sealed at the necessary locations. It is for this purpose that the packing assemblies P and P are provided above and below the gas lift valve assembly V for sealing against the wall of the tubing string. Any suitable type of packing assembly may be provided. The ones shown P P are illustrated as ofthe type provided with packing rings 6 and 7. Packing assemblies P, and P are connected to the gas lift valve assembly V by suitable ball and socket joints 8 and 9, respectively. In addition, the lower packing assembly P, is connected to the latch assembly L by a similar ball and socket joint 10. These ball and socket joints allow the various components to manipulate short radius curvatures through which the assembly may pass, e.g. flow loops and flowlines to which the well is connected.

A running and pulling adaptor A may be connected to the upper packing assembly P by a ball and socket joint 11. The adaptor A is provided with a running and pulling neck 12 by which the entire assembly therebelow is connected to the remaining portion of the pumpdown assembly thereabove. The adaptor A is also provided with a port 13 which allows bypassing fluids pushed ahead of the motor units M -M The running and pulling tool T, of a special design, is the subject of the present invention. It will be described in detail hereafter. For present. purposes it is sufficient to note that the running tool T is designed for selective engagement with and disengagement from the running and pulling neck 12 of adaptor A.

The running and pulling tool T is connected by a suit able ball and socket joint 14 to the lowermost motor unit M Additional motor units M -M are connected by similar ball and socket joints l5, l6 and 17. The lower motor unit M may be provided with a packing 18 and a resilient lip type seal 19. The other motor units M -M are also provided with resilient lip type seals 20, 21 and 22. As can readily be seen, some of these lip type seals 19 and 20 slant in one direction while others 21 and 22 slant in the opposite direction. This is to facilitate bidirectional movement of the pumpdown train. The upwardly slanting seals 21, 22 are primarily for pumping the assembly downwardly into the well, during running operations, while the downwardly slanting seals 19, 20 are primarily for pumping the pumpdown train out of the well, e.g. during pulling operations. The emergency pulling neck N may be attached to the upper motor unit M by a suitable ball and socket joint 23.

Referring now to FIG. 2, the running and pulling tool T will be described in detail. The tool T comprises a tubular body 30, biasing means 31, a plurality of latches 32 and cam means 33. The tubular body 30 is provided with a plurality of elongated radial windows 34, the upper ends of which terminate in shoulder 35 and the lower ends of which terminate in tapered stop shoulder 36. The stop shoulder 36 serves a stopping or lock function to be further described hereafter. An annular slot 37 is cut on the interior of the tubular body 30 to receive a portion of the latches 32, as will be described hereafter. The interior of the body member 30 is also counterbored at 38 to receive a portion of the biasing means 31.

The upper end of the body 30 is spherically machined to form the ball portion 39 of a ball and socket joint, i.e., 14 in FIG. 1A. The upper interior of the body 30 at the ball portion 39 is provided with helical threads 40. These threads 40 serve a retaining function to be described hereafter. A hole 41 is provided in the wall of body member30 to allow the insertion of a shear pin (not shown in FIG. 2) which is primarily used during pulling operations as will be explained hereafter. The outside diameter of the body member is reduced in the area of the hole 41 to allow placement of a shear pin retainer cap 67 for holding the shear pin in place as will be described hereafter. An annular groove 42 may also be provided for a snap ring 68 to hold the retainer cap in place.

The latches 32 comprise an intermediate pivot portion 43 connecting finger portions 44, depending downwardly therefrom, and heel portions 45, extending upwardly therefrom. The pivot portion 43 is provided with a raised fulcrum 46 about which the latches are pivotable between a retracted position, as shown in FIG. 2, and an extended position, unless otherwise hindered, in which the tips of latch fingers 44 are outwardly extended. The heel portion 45 is provided with a lug like extension 47 which engages the body member slot 37 and functions to retain the latches 32 on the body 30. The axial dimension of the lugs 47 is smaller than the slot 37 so as to allow limited longitudinal or axial movement of the latches 32 relative to the body member 30. The fingers 44 are provided with inwardly directed lug like tips 48, the primary purpose of which is to engage the annular groove 12a of the running neck 12 of running and pulling adaptor A. The finger tips 48 are provided with inwardly and outwardly tapered cam surfaces 49 and 50, the purposes of which will be more fully understood hereafter.

The biasing means 31 may comprise an annular bearing ring 52 and a helically wound spring 53, forcing the bearing ring 52 against the heel portion 45 of the latches 32. The bearing ring 52 is provided with a tapered surface 54 which cooperates with a corresponding tapered surface on the heel portion 45 to bias latches 32 toward the retracted position shown in FIG. 2.

The cam means 33 comprises a cylindrical body 55 connected to an enlarged head portion 56 by an intermediate diameter portion 57. The outer surfaces of the body portion 55 and intermediate portion 57 are connected by a tapered annular cam surface 58. Extending upwardly from the opposite end of the cylindrical body portion 55 is a plurality of collet fingers 59 on the ends of which are outwardly projecting lugs 60. These lugs 60 are provided with male threads 61 which correspond with the female threads 40 on the interior of the body member 30. The collet fingers 59 cooperate with the body threads 40 in a retaining function to be described hereafter.

Were it not for the engagement of the collet finger threads 61 with body threads 40, the cam means 33 would be free to reciprocate axially, within certain limits, within the interior of body member 30. If enough axial force is applied to the cam means 33, the collet fingers 59 will be flexed inwardly and outwardly, allowing the cam means 33 to be axially displaced anyway. In addition, the opposite ends of the cam means 33 may be provided with transverse slots 62 and 63, by which the cam means 33 may be rotated with a suitable tool, Le, a screwdriver. Rotation of the cam means in this manner will also serve to axially displace the cam means, relative to the body 30, through the threading advancement of male threads 61 within female threads 40. A shear pin hole 64 may be provided in the body portion of the cam means 33 to cooperate with the pin hole 41ofthe body member 30 as will be more fully understood hereafter. Another hole 65 may be provided to allow displacement of broken shear pins from hole 41 as will be more fully understood hereafter.

STATEMENT OF OPERATION 1. Running Operation 1 Referring now primarily to FIGS. 1A. 1B, 2 and 3, the operation of the running and pulling tool T will be explained. This operation is to be explained for installation of a gas lift valve assembly such as V. It should, however, be understood that many other types of downhole devices may be installed with this type of running and pulling tool.

Initially, the entire pumpdown train is assembled as shown in FIGS. 1A and 1B. The motor units M,M, are connected to the running and pulling adaptor A and all components therebelow; latches L, valve assembly V, packing assemblies P and P,; by the running and pulling tool T of the present invention. This is accomplished simply by applying an axial force to the running and pulling tool T as the adaptor neck 12 is inserted through the lower end of tubular body 30. The cam surface 49 on the latch fingers 44 causes the latches 32 to be axially displaced and slightly extended until the lugs 48 pass the annular flange 12 and engage the annular recess 12,. The biasing afforded by the biasing means 31 then causes the latches 32 to snap back into place, as shown in FIG. 2. The latches are held in position by the biasing of the biasing means 31 and the tapered stop surface 36.

After the pumpdown train is assembled and placed in the tubing string or a flowline connected thereto, hydraulic pressure is applied to the upper or motor end of the assembly, forcing the entire train down the tubing string. Downward movement is finally arrested by engagement of the latch assembly latches l with cooperating recesses within the corresponding tubing receiver. At this point the latch assembly L packing assemblies P P and gas lift valve assembly V are properly located and installed within the receiver. No further description of this latching operation is needed since such is already known in the prior art.

To release the running and pulling tool T and all components of the train thereabove from the running and pulling adaptor A and the components therebelow, additional pressure is applied through the tubing string. By this time, the cam head 56 is bearing against the upwardly facing surface 12c of annular flange 12b. When this pressure reaches a preselected level, e.g. 750 psi, the collet fingers 59 are alternately retracted and expanded, allowing the cam means 33 to be axially displaced in an upward direction, relative to the body member 30, finally assuming the position shown in FIG. 3. As the cam means 33 is axially displaced cam surface 58 engages latch fulcrum 46 causing the latches 32 first to be displaced axially upwardly, clearing the stop surface 36, then to pivot outwardly freeing the fingertips 48 from the running neck groove 12a. The latches 32 are then maintained in this position, since the cam means 33 is maintained in its upwardly displaced position by the engagement of collet finger threads 61 with the body threads 40.

Then all that is required to remove the running and pulling tool T and the remainder of the pumpdown train, is to apply hydraulic pressure below the motor units M M.,, through the surrounding casing string or any other suitable arrangement, reversing the direction of the motor units. The motor units M M and running and pulling tool T then exit the well through the tubing and flowline, if such is connected thereto.

2. Pulling Operation The same running and pulling tool T used in running a device into a well may be used for pulling such a device out of the well with little or no modification. To place the running and pulling tool T in the pulling position, it is first necessary to return the cam means 33 to the initial position shown in FIG. 2. This may be accomplished in two ways:

a. by applying downwardly directed axial force to the cam means 33, causing the collet fingers to be alternately retracted and expanded, until it assumes the position of FIG. 2; or

b. rotating the cam means 33 with a screwdriver, or the like, until it assumes the same position.

The running and pulling tool T could then be run into the hole for retrieving the well device previously installed therein. However, before running into the hole, provision may be made for emergency conditions in which the well device, and consequently the running and pulling tool T, may become stuck in the well. A shear pin 66 may be inserted into aligned holes 41 and 64 in the body and cam means 30, 33, respectively. A retainer cap 67 may be placed around the body and a snap ring 68 may be inserted into annular groove 42 to prevent the shear pin 66 from working out of its place. (See FIG. 4) The functioning of the shear pin 66 will be described hereafter.

After the running and pulling tool T is thus set and assembled with motor units M M the unloaded train is reinserted into the tubing string and pumped downwardly therein toward the running and pulling adaptor A. Upon initial engagement with the flange lip 12b of adaptor A, the latches 32 are displaced slightly upwardly, relative to body 30, and pivoted outwardly by cam surface 49, until the finger lugs 48 are free to pass flange lip 12b and reengage groove 12a. (See FIG. 4.) Then an upwardly directed force is applied to the running and pulling tool T by reversing the hydraulic pressures in the tubing string so that a pressure differential is created which causes the motor units M,M to apply an upwardly directed force to the pumpdown train. When a sufficient force is applied, the gas lift valve latch assembly L is released, allowing the latch assembly L, gas lift valve assembly V and associated components to be removed from the tubing string. During this operation, the latches 44 are prevented from disengaging adaptor A, by the engagement of latch surfaces 50 with the stop shoulder 36 of the body member 30. (See also FIG. 2.)

The foregoing pulling operation is that which would by typically encountered. However, occasionally the device to be pulled may become stuck within the tubing string. For example, the latch assembly L may fail to function due to corrosion, buildup of deleterious materials, or other reasons. In such a case, it may be desirable to release the running and pulling tool T, along with the motor units M,-M for removal from the well so that remedial equipment may be introduced thereinto. It is for this reason that the shear pin 66 is provided. If the gas lift valve assembly V is not released by normal forces, then pressure would again be applied in the tubing above the motor units M M until a sufficient pressure, e.g. 3,000 psi, is reached to shear pin 66. Once pin 66 has been sheared, cam means 33 is again free to be axially displaced upwardly, as shown in FIG. 5, extending the latches 32 and releasing them from engagement with the adaptor neck 12. They are retained in this position by the engagement of collet finger threads 61 with the body threads 40 and, after shearing of the pin 66, the releasing of the running and pulling tool T is identical to the release described in the running operation. The running and pulling tool T and the motor units M M may then be completely removed from the well so that remedial action may be taken to free the stuck valve assembly V and its associated assemblies.

The broken shear pin 66 would be removed from the tool T for replacement by another pin, if so desired. The portion of broken pin 66 remaining in the body 30 (See FIG. 5) could be removed, after removal of cap 67 or rotation thereof for alignment of a hole therein (not shown) with hole 41. This could be done by placing a punch or other tool through a hole (not shown), similar to 41 and therefrom, on body 30 and hole 65, which is aligned with hole 41 on displacement of the cam means 33, as in FIG. 5.

From the foregoing description, it can readily be seen that the running and pulling tool of the present invention offers many advantages. Not only can the same tool be used for both running and pulling, it can be so used without any further modification. Furthermore, it can also be provided with emergency release apparatus which is very simple to install and operate. In fact the entire running and pulling tool of the present invention is extremely versatile, simple to oprate and economic to manufacture.

Although a single preferred embodiment of the invention has been described herein, many variations thereof may be made by those skilled in the art without departing from the spirit of the invention. It is, therefore, intended that the scope of the invention be limited only by the claims which follow.

I claim:

1. Well, tool apparatus for selective engagement with and disengagement from a well device comprising:

a. tubular body means having radial windows therein;

b. a plurality of latches carriedby said body means for radial movement in said windows between retracted positions, engaging said well device, and extended positions, disengaging said well device;

c. cam means carried by said body means and axially movable relative thereto to effect movement of said latches between said retracted and extended positions; and

d. cooperable retainer means comprising retractable and expandable collet means, carried by one of said body means and said cam means, engageable with corresponding groove means carried by the other, permitting said axial movement of said cam means in response to a predetermined axial force applied thereto, said retainer means also comprising a frangible member connecting said body means and said cam means, said member being frangible in response to an axial force greater than said predetermined axial force to release said cam means for response to said predetermined axial force and operation of said collet means.

2. Well tool apparatus as set forth in claim 1 in which said latches comprise pivot means and longitudinally disposed finger means extending therefrom, said latches being pivotable about said pivot means between said retracted and extended positions.

3. Well tool apparatus as set forth in claim 2 in which said latches also comprise heel means by which said latches are retained on said body means, said heel means engaging slots provided therefor on said body means permitting limited axial movment of said latches between first and second terminal positions, stop means being provided on said body means for engagement with said latch finger means, when at said first terminal position, to prevent said movement of said latches to said extended positions.

4. Well tool apparatus as set forth in claim 3 including biasing means carried by said body means and engaging said latches biasing said latches toward said first terminal position.

5. Well tool apparatus as set forth in claim 2 in which said pivot means comprises cam surfaces engageable with cam surfaces on said cam means, in response to axial displacement of said cam means, to effect pivotable movement of said latches to said extended positions.

6. Well tool apparatus as set forth in claim 5 in which said retainer means is operable upon removal of said predetermined force to retain said cam means in said axially displaced position and to retain said latches in said extended positions.

7. Well tool apparatus for selective engagement with and disengagement from a well device comprising:

a. tubular body means having radial windows therein;

b. a plurality of latches carried by said body means for radial movement in said windows between retracted positions, engaging said well device, and extended positions, disengaging said well device;

c. cam means carried by said body means and axially movable relative thereto to effect movement of said latches between said retracted and extended positions; and

d. cooperable retainer means carried by said body means and said cam means permitting said axial movement of said cam means in response to a predetermined axial force applied thereto;

e. said retainer means comprising retractable and expandable collet means, carried by one of said cam means and body means, engageable with corresponding groove means carried by the other, said groove means comprising a set of helical threads, said collet means having corresponding threads engageable therewith and being alternately retractable and expandable in response to said predetermined axial force to permit axial displacement of said cam means relative to said body means;

. said cam means being provided with rotation means by which said cam means may be rotated for axial displacement relative to said body means through the threaded engagement of said collet means and said groove means.

8. Well tool apparatus for selective engagement with and disengagement from a well device comprising:

a. tubular body means;

b. a plurality of latches carried by said body means,

having pivot means and longitudinally disposed finger means extending therefrom, said latches being pivotable about said pivot means to permit radial movement of the tips of said finger means between retracted and extended positions;

c. biasing means carried by said body means, biasing said finger means toward said retracted position; (1. cam means carried by said body means and comprising a cylindrical member axially movable, relative thereto, and slidingly engageable with said latches to effect said pivoting of said latches between said retracted and extended positions; and

e. cooperable retainer means carried by said cam means and said body means permitting said axial movement of said cam means in response to a predetermined axial force applied thereto but preventing axial movement of said cam means in response to axial forces less than said predetermined axial force, said retainer means comprising a plurality of collet fingers on said cam means having toothed tips which are engageable with corresponding toothed surfaces on said body means.

9. Well tool apparatus as set forth in claim 8 in which said toothed tips and said toothed surfaces comprise corresponding threads on said collet finger tips and said body means, said collet finger tips being inwardly movable and disengageable from a first portion of said body means threads, in response to said predetermined axial force, to permit said axial movement of said cam means and reengagement of said collet finger tips with a second portion of said body means threads axially spaced from said first portion.

10. Well tool apparatus as set forth in claim 9 in which said corresponding threads are helical threads, said cam means also being axially movable in response to rotation of said cam means through cooperating threading between said threaded collet finger tips and body means.

11. Well tool apparatus as set forth in claim 8 in which said retainer means also comprises a frangible member connecting said cam meanas and said body means, said frangible means being frangible in response to an axial force greater than said predetermined axial force to release said cam means for response to said predetermined axial force.

12. Well tool apparatus as set forth in claim 8 in which said latches also comprise heel means engaging a slot on said body means so as to permit said pivoting of said latches without disengaging said slot.

13. Well tool apparatus as set forth in claim 12 in which said slot is of a sufficient width to permit limited axial travel of said latches relative to said body means.

14. Well tool apparatus as set forth in claim 13 in which said biasing means comprises an annular collar member bearing against said latch heel means and a spring member axially disposed between said collar member and an annular shoulder on said body means biasing said latches toward one terminal of said limited axial travel.

15. Well tool apparatus as set forth in claim 14 in which said body means is provided with stop means engaging the tips of said finger means when said latches are at said one terminal to prevent movement to said extended positions, said latches being disengaged from said stop means, when said latches are at the opposite terminal, to allow movement to said extended positions. 

1. Well tool apparatus for selective engagement with and disengagement from a well device comprising: a. tubular body means having radial windows therein; b. a plurality of latches carried by said body means for radial movement in said windows between retracted positions, engaging said well device, and extended positions, disengaging said well device; c. cam means carried by said body means and axially movable relative thereto to effect movement of said latches between said retracted and extended positions; and d. cooperable retainer means comprising retractable and expandable collet means, carried by one of said body means and said cam means, engageable with corresponding groove means carried by the other, permitting said axial movement of said cam means in response to a predetermined axial force applied thereto, said retainer means also comprising a frangible member connecting said body means and said cam means, said member being frangible in response to an axial force greater than said predetermined axial force to release said cam means for response to said predetermined axial force and operation of said collet means.
 2. Well tool apparatus as set forth in claim 1 in which said latches comprise pivot means and longitudinally disposed finger means extending therefrom, said latches being pivotable about said pivot means between said retracted and extended positions.
 3. Well tool apparatus as set forth in claim 2 in which said latches also comprise heel means by which said latches are retained on said body means, said heel means engaging slots provided therefor on said body means permitting limited axial movment of said latches between first and second terminal positions, stop means being provided on said body means for engagement with said latch finger means, when at said first terminal position, to prevent said movement of said latches to said extended positions.
 4. Well tool apparatus as set forth in claim 3 including biasing means carried by said body means and engaging said latches biasing said latches toward said first terminal position.
 5. Well tool apparatus as set forth in claim 2 in which said pivot means comprises cam surfaces engageable with cam surfaces on said cam means, in response to axial displacement of said cam means, to effect pivotable movement of said latches to said extended positions.
 6. Well tool apparatus as set forth in claim 5 in which said retainer means is operable upon removal of said predetermined force to retain said cam means in said axially displaced position and to retain said latches in said extended positions.
 7. Well tool apparatus for selective engagement with and disengagement from a well device comprising: a. tubular body means having radial windows therein; b. a plurality of latches carried by said body means for radial movement in said windows between retracted positions, engaging said well device, and extended positions, disengaging said well device; c. cam means carried by said body means and axially movable relative thereto to effect movement of said latches between said retracted and extended positions; and d. cooperable retainer means carried by said body means and said cam means permitting said axial movement of said cam means in response to a predetermined axial force applied thereto; e. said retainer means comprising retractable and expandable collet means, carried by one of said cam means and body means, engageable with corresponding groove means carried by the other, said groove means comprising a set of helical threads, said collet means having corresponding threads engageable therewith and Being alternately retractable and expandable in response to said predetermined axial force to permit axial displacement of said cam means relative to said body means; f. said cam means being provided with rotation means by which said cam means may be rotated for axial displacement relative to said body means through the threaded engagement of said collet means and said groove means.
 8. Well tool apparatus for selective engagement with and disengagement from a well device comprising: a. tubular body means; b. a plurality of latches carried by said body means, having pivot means and longitudinally disposed finger means extending therefrom, said latches being pivotable about said pivot means to permit radial movement of the tips of said finger means between retracted and extended positions; c. biasing means carried by said body means, biasing said finger means toward said retracted position; d. cam means carried by said body means and comprising a cylindrical member axially movable, relative thereto, and slidingly engageable with said latches to effect said pivoting of said latches between said retracted and extended positions; and e. cooperable retainer means carried by said cam means and said body means permitting said axial movement of said cam means in response to a predetermined axial force applied thereto but preventing axial movement of said cam means in response to axial forces less than said predetermined axial force, said retainer means comprising a plurality of collet fingers on said cam means having toothed tips which are engageable with corresponding toothed surfaces on said body means.
 9. Well tool apparatus as set forth in claim 8 in which said toothed tips and said toothed surfaces comprise corresponding threads on said collet finger tips and said body means, said collet finger tips being inwardly movable and disengageable from a first portion of said body means threads, in response to said predetermined axial force, to permit said axial movement of said cam means and reengagement of said collet finger tips with a second portion of said body means threads axially spaced from said first portion.
 10. Well tool apparatus as set forth in claim 9 in which said corresponding threads are helical threads, said cam means also being axially movable in response to rotation of said cam means through cooperating threading between said threaded collet finger tips and body means.
 11. Well tool apparatus as set forth in claim 8 in which said retainer means also comprises a frangible member connecting said cam means and said body means, said frangible means being frangible in response to an axial force greater than said predetermined axial force to release said cam means for response to said predetermined axial force.
 12. Well tool apparatus as set forth in claim 8 in which said latches also comprise heel means engaging a slot on said body means so as to permit said pivoting of said latches without disengaging said slot.
 13. Well tool apparatus as set forth in claim 12 in which said slot is of a sufficient width to permit limited axial travel of said latches relative to said body means.
 14. Well tool apparatus as set forth in claim 13 in which said biasing means comprises an annular collar member bearing against said latch heel means and a spring member axially disposed between said collar member and an annular shoulder on said body means biasing said latches toward one terminal of said limited axial travel.
 15. Well tool apparatus as set forth in claim 14 in which said body means is provided with stop means engaging the tips of said finger means when said latches are at said one terminal to prevent movement to said extended positions, said latches being disengaged from said stop means, when said latches are at the opposite terminal, to allow movement to said extended positions. 